Transport Method and Transport Apparatus

ABSTRACT

Provided is a transport method comprising judging whether there is a possibility that misalignment greater than or equal to a threshold value occurs between substrates to be layered that are held by a pair of substrate holders aligned and stacked by an aligning section, the misalignment occurring when the pair of substrate holders is transported from the aligning section to a pressure applying section; and if the judgment indicates that there is the possibility of misalignment, transporting the pair of substrate holders to a region other than the pressure applying section. Whether there is the possibility of misalignment may be judged based on acceleration of the substrate holders. Whether there is the possibility of misalignment may be judged based on acceleration of a transporting section that transports the substrate holders. Whether there is the possibility of misalignment may be judged based on relative positions of the substrate holders. Whether there is the possibility of misalignment may be judged based on relative positions of (i) a transporting section that transports the pair of substrate holders and (ii) one of the pair of substrate holders.

BACKGROUND

1. Technical Field

The present invention relates to a transport apparatus and a transportmethod. In particular, the present invention relates to a transportmethod of a substrate holder during manufacturing of a layered3-dimensional semiconductor apparatus and an apparatus that realizesthis transport method. The present patent application claims prioritybased on Japanese Patent Publication Application No. 2007-164081 filedon Jun. 21, 2007, the contents of which are incorporated herein byreference.

2. Related Art

Techniques are advancing for bonding substrates, wafers, and the like toeach other during manufacturing of a device having a stereoscopicstructure such as a MEMS or a layered 3-dimensional semiconductorapparatus having layered wafer levels. The development of apparatusesused for this purpose is also progressing. For example, see JapanesePatent Application Publication No. 2005-302858. With such a bondingapparatus, when transporting a temporarily fixed layered wafer body,transportation conditions are adopted so as not to cause misalignmentbetween the wafers.

Regarding the transport conditions of the bonding apparatus, ifmisalignment is caused for some reason after two wafers are aligned andthe misaligned wafers then undergo electrode bonding by a pressureapplying and heating process, the resulting layered semiconductorapparatus does not function properly, which causes a drop in the yieldwhen manufacturing semiconductor apparatuses. Therefore, transport ofthe aligned wafers without causing misalignment is desired, and so isdetection of misalignment between the wafers prior to the pressureapplying and heating process.

SUMMARY

Therefore, according to a first aspect related to the innovationsherein, one exemplary transport method may comprise judging whetherthere is a possibility that misalignment greater than or equal to athreshold value occurs between substrates to be layered that are held bya pair of substrate holders aligned and stacked by an aligning section,the misalignment occurring when the pair of substrate holders istransported from the aligning section to a pressure applying section;and if the judgment indicates that there is the possibility ofmisalignment, transporting the pair of substrate holders to a regionother than the pressure applying section.

According to a second aspect related to the innovations herein, oneexemplary transport apparatus may include a transport apparatus thattransports a pair of substrate holders, which are aligned and stacked byan aligning section and hold substrates to be layered, from the aligningsection to a pressure applying section, comprising a control sectionthat (i) judges whether there is a possibility of misalignment greaterthan or equal to a threshold value occurring between the substrates, themisalignment occurring during transport from the aligning section to thepressure applying section, and (ii) if the judgment indicates thepossibility of misalignment, causes the pair of substrate holders to betransported to a region other than the pressure applying section.

According to a third aspect related to the innovations herein, oneexemplary transport method may comprise judging whether there is apossibility that misalignment greater than or equal to a threshold valueoccurs between substrates aligned and stacked by an aligning section,the misalignment occurring when the pair of substrates is transportedfrom the aligning section to a pressure applying section; and if thejudgment indicates that there is the possibility of misalignment,transporting the pair of substrates to a region other than the pressureapplying section.

According to a fourth aspect related to the innovations herein, oneexemplary transport apparatus may include a transport apparatus thattransports a pair of substrates, which are aligned and stacked by analigning section, from the aligning section to a pressure applyingsection, comprising a control section that (i) judges whether there is apossibility of misalignment greater than or equal to a threshold valueoccurring between the substrates, the misalignment occurring duringtransport from the aligning section to the pressure applying section,and (ii) if the judgment indicates the possibility of misalignment,causes the pair of substrates to be transported to a region other thanthe pressure applying section.

The summary clause does not necessarily describe all necessary featuresof the embodiments of the present invention. The present invention mayalso be a sub-combination of the features described above. The above andother features and advantages of the present invention will become moreapparent from the following description of the embodiments taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart showing the manufacturing process of a layered3-dimensional semiconductor apparatus.

FIG. 2A is a schematic view of one step performed by the manufacturingapparatus.

FIG. 2B is a schematic view of one step performed by the manufacturingapparatus.

FIG. 2C is a schematic view of one step performed by the manufacturingapparatus.

FIG. 3A is a schematic view of one step performed by the manufacturingapparatus.

FIG. 3B is a schematic view of one step performed by the manufacturingapparatus.

FIG. 3C is a schematic view of one step performed by the manufacturingapparatus.

FIG. 4 is a schematic view of one step performed by the manufacturingapparatus.

FIG. 5A shows the transport apparatus 42 as seen from the side when theblock 27 is loaded therein.

FIG. 5B shows the transport apparatus 42 as seen from the directionindicated by A in FIG. 5A when the block 27 is loaded therein.

FIG. 6 is a graph showing the correlation between the accelerationimparted by the transport apparatus 42 and the amount of misalignmentoccurring between the wafers 11.

FIG. 7 shows a first modification of the present embodiment.

FIG. 8 shows the transport apparatus 42 according to the secondembodiment, as viewed from the side in a state where the block 27 isloaded therein.

FIG. 9 shows the transport apparatus 42 according to the thirdembodiment, as viewed from the side in a state where the block 27 isloaded therein.

FIG. 10 is a schematic view of a control section 80 and the transportapparatus 42 according to the fourth embodiment.

FIG. 11 is a side view of the transport apparatus 42 according to thefifth embodiment when the block 27 is loaded therein.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, some embodiments of the present invention will bedescribed. The embodiments do not limit the invention according to theclaims, and all the combinations of the features described in theembodiments are not necessarily essential to means provided by aspectsof the invention.

FIG. 1 is a flow chart showing the manufacturing process of a layered3-dimensional semiconductor apparatus. FIGS. 2A, 2B, 2C, 3A, 3B, 3C, and4 each show a manufacturing apparatus and work occurring at each stageof the manufacturing process shown in FIG. 1. The following uses theseFigures to described the process of FIG. 1.

Wafer Preparation Step (S1):

In the wafer preparation step, a wafer 11 is prepared on which is formedcircuit elements implemented in the final chip form, as shown in FIG.2A. In this step, a wafer 11 is created on which is formed asemiconductor apparatus 13 including transistors, resistors, capacitors,wiring, via-electrodes, and the like, using mainly a lithographytechnique and also an impurity expansion technique, an etchingtechnique, a thin-film forming technique, or the like.

The wafer 11 is prepared so as to have a number of layers required forforming an IC chip to be ultimately used. Layering of the wafer 11 maybegin after the desired number of layers is prepared, or a portion ofthe layering step may be performed in parallel with the preparation.

Wafer Holding Step (S2):

In the wafer holding step (S2), the wafer 11 is held on a wafer holder21 by electrostatic adsorption, as shown in FIG. 2B. By holding anotherwafer 11 in another wafer holder 21, the wafer holders 21 can hold awafer 11 pair made of two stacked wafers 11. The method for holding thewafers 11 is not limited to electrostatic adsorption, and may instead bevacuum suction or the like, One of the held wafers 11 may already have a3-dimensional structure formed by layering and bonding a plurality ofsubstrates.

In the wafer holding step (S2), the positional relationship between theeach pair of a wafer holder 21 and a wafer 11 is recorded by using amicroscope or the like to measure an alignment mark 23 on the wafer 11held by the wafer holder 21 and a reference mark 25 on the wafer bolder21. This record is used in the following step. Furthermore, as describedfurther below, this record is also used when judging whether there is apossibility of misalignment between the wafer 11 and the wafer holder21.

Wafer Stacking Step (S3):

In the wafer stacking step (S3), the wafers held by the wafer holders 21are brought near each other with their surfaces opposed to each other,as shown in FIG. 2C. The positional relationship between the referencemarks 25 of the wafer holders 21 is monitored by a microscope 31 tomeasure the positional relationship between corresponding referencemarks 25 on the wafer holders 21.

By referencing the positional relationships between the wafer holders 21and the wafers 11 recorded in the previous step, the relative positionsof the reference marks 25 of the wafer holders 21 and the alignment mark23 of the wafers 11 can be obtained. By moving one of the wafer holders21 by an appropriate amount relative to the other wafer holder 21 basedon these relative positions, the alignment marks 23 on a pair of wafers11 can be brought into alignment with each other. Each reference mark 25on each wafer holder 21 is formed on a substrate that is thinly layeredover a concave portion 33 formed in the wafer holder 21, such thatreference mark 25 can be observed by the microscope 31 or the like froma back surface of the wafer holder 21.

Wafer Temporary Fixing Step (S4):

In the wafer temporary fixing step (S4), the space between two alignedwafers 11 is narrowed, such that the two wafers 11 are stacked incontact. After stacking the wafers, the pair of wafer holders 21temporarily affix the wafers 11 to each other by inserting a pluralityof temporary fixing apparatuses 41 into concave portions 29 formed onthe periphery of the wafer holders 21, as shown in FIG. 3A.

Each temporary fixing apparatus 41 exerts a force perpendicular to thesurfaces of the wafers on the wafer holders 21, but does not exert anyforce parallel to these surfaces. In this way, the two wafers 11 arealigned with each other, and a block 27 is achieved by temporarilyfixing the wafers 11 to each other in a contacting state.

Transportation Step and Detection of Misalignment Between Wafers (S5):

As shown in FIG. 3B, in the manufacturing apparatus 40 that manufacturesthe semiconductor apparatus, the temporarily fixed block 27 istransported from the stacking step executing section 45 to the pressureapplying and heating step executing section 47. The transport of theblock 27 is performed by the transport arm 43 of the transport apparatus42. During the transport period, that is, the period from when the block27 begins being transported from the stacking step executing section 45to when the block 27 arrives at the pressure applying and heating stepexecuting section 47 and the pressure applying and heating step begins,a method described further below is used to detect the possibility ofmisalignment occurring between the two wafers 11.

The transport apparatus 42 controls the operation of the transport arm43 such that misalignment does not occur between the wafer holders 21and the wafers 11 in the transported block 27. Even so, misalignmentmight be caused by sudden stoppage of the transport apparatus 42 when acontrol system above the transport apparatus 42 detects some kind ofabnormality.

In this case, the movement of the transport arm 43 is stopped suddenlyregardless of the transport apparatus 42, causing a large accelerationof the wafer holders 21 and wafers 11 during transport. Also, if thepower supply is suddenly cut for some reason, the control of thetransport apparatus 42 is disabled, causing the transport arm 43 to stopand resulting in a large acceleration of the wafer holders 21 and wafers11.

If the transport apparatus 42 is provided with a plurality ofindependently controlled actuators, each actuator is controlled suchthat wafer holder 21 misalignment does not occur. However, there arecases where the tolerance of each actuator is overlapped such that thetransported wafer holders 21 accelerate beyond a setting amount, whichcauses a large acceleration of the block 27.

In such a case, the transport arm tip 60 is provided with anacceleration sensor 64, for example, that can detect the possibility ofmisalignment by detecting the acceleration actually imparted to theblock 27. On the other had, if a control system of the transportapparatus 42 detects an abnormality of some sort, the output of theacceleration sensor 64 can be referenced to detect whether theabnormality affects the block 27.

Misalignment Possibility Judging Step (S6):

In the misalignment possibility judging step (S6), a judgment is madeconcerning the detected possibility of misalignment. If the detectedacceleration is below a threshold value indicating that there is nopossibility of misalignment, the process moves to the pressure applyingand heating step (S7). In other words, the judgment concerning thepossibility of misalignment based on acceleration may be performedimmediately prior to the initiation of the pressure applying and heatingstep. As a result, the performance of the pressure applying and heatingstep on a misaligned block 27 is prevented, thereby preventing a drop inthe yield.

On the other hand, if the detection result indicates there is apossibility that the two wafers 11 are misaligned and the alignmentprecision necessary for the layered bonding is not ensured, the pressureapplying and heating step (S7) is performed after returning the block 27to the stacking step executing section 45 and repeating the steps fromS3 to S5. As a result, precise alignment of the wafers 11 can beensured.

The actual transport of a block 27 that is possibly misaligned to thepressure applying and heating step executing section 47 may be stopped.Instead of stopping transport of the block 27, the operation of thepressure applying and heating step executing section 47 may be stopped.Therefore, a block 27 that is possibly misaligned is removed from thetransportation path and instead transported to a different region thatis described further below.

Such a block 27 may be transported to a region other than the pressureapplying and heating step executing section 47 by the transportapparatus 42. In this case, the block 27 may accumulate thepossibly-misaligned wafers in a wafer cassette or the like designed forthis purpose, without performing the pressure applying and heating step.Furthermore, if the possibly-misaligned blocks 27 are transported to aregion other than the pressure applying and heating step executingsection 47, the steps from S3 to S5 may be performed for other wafers11.

Even if the possibility of misalignment is detected, that does notactually mean that the block 27 is misaligned. Such a block 27 that isnot actually misaligned is examined to detect whether misalignment hasoccurred, and can move to the pressure applying and heating step withoutrepeating the stacking step. As a result, the number of times that thestacking step is repeated can be decreased, thereby enhancing thethroughput when manufacturing layered semiconductor apparatuses.

If a state of a wafer 11 changes during the stacking step, e.g. ifsurface quality of the bonded surface changes, it might be impossible tore-perform the stacking step for the misaligned block 27 in this state.In such a case, the stacking step is re-performed after a process isperformed to polish the surface of the wafer 11, for example. As aresult, the quality of the block 27 on which the stacking step isre-performed is improved, thereby further increasing the yield whenmanufacturing layered semiconductor apparatuses.

Pressure Applying and Heating Step (S7):

The block 27 transported to the pressure applying and heating stepexecuting section 47 is loaded in the pressure applying and heating stepexecuting section 47, the degree of parallelization between the upperpressure applying plate 49 and the lower pressure applying plate 48 ofthe pressure applying and heating step executing section 47 is adjusted,and the upper pressure applying plate 49 is pressed toward the lowerpressure applying plate 48 using a hydraulic cylinder, for example, asshown in FIG. 3C. After the two wafers 11 have been pressed by the waferholders 21, the wafers 11 are heated by heaters housed in the waferholders 21 and the electrodes are bonded to form the layered wafer body50, as shown in FIG. 4

An adhesive agent or the like may be used when affixing the wafers 11 toeach other in the pressure applying and heating step. In such a case,the heating of the block 27 by the pressure applying and heating stepexecuting section 47 can be omitted.

The pressure applying and heating step executing section 47 may have aconfiguration for transporting the block 27 internally. As a result,even after the block 27 is transported into the pressure applying andheating step executing section 47, misalignment might occur in the block27. Therefore, a step may be included to detect the possibility ofmisalignment prior to the initiation of the pressure applying process.

When the possibility of misalignment is detected in this step, theoperation of the pressure applying and heating step executing section 47may be stopped and the block 27 may be transported to another regionwithout undergoing the pressure applying and heating step. In the samemanner as described above, the transported blocks 27 may be realigned ormay be transported and accumulated in a prescribed region after beingexamined. As a result, the manufacturing yield of layered semiconductorapparatuses is improved.

Dicing Step (S8):

The layered wafer body 50, which is formed by layering a prescribednumber of wafers 11 and bonding the electrodes, is diced to be separatedinto individual chips 51, as shown in FIG. 4. The dicing can be realizedby cutting the layered wafer body 50 along the dotted lines shown inFIG. 4, for example, using a widely known dicing blade.

As described above, by using the layered 3-dimensional semiconductorapparatus manufacturing apparatus and manufacturing method according tothe embodiments of the invention, a drop in the yield of layered3-dimensional semiconductor apparatuses due to bonding defects caused bymisalignment during transport can be prevented by changing the stepswhen the possibility of misalignment between transported stacked wafers11 is detected.

Therefore, a transport method is realized in which, when wafers 11 to bestacked are held by a pair of wafer holders 21, which are aligned by thestacking step executing section 45, and transported from the stackingstep executing section 45 to the pressure applying and heating stepexecuting section 47, a judgment can be made concerning the possibilitythat misalignment greater than a threshold amount occurs between thewafers 11. If this possibility is judged to be high, the pair of waferholders 21 are transported to a region other than the stacking stepexecuting section 45.

The following is a description, referencing Figures, of embodiments ofthe transport method and transport apparatus for detecting thepossibility of misalignment. In the following description, componentsthat have appeared previously are given the same reference numerals andredundant explanation is omitted.

First Embodiment

FIGS. 5A and 513 show the transport apparatus 42 that detectsmisalignment according to the first embodiment. FIGS. 5A and 5B show thetransport apparatus 42 when a block 27 is loaded therein, as shown inFIG. 3B. FIG. 5A shows the transport apparatus 42 as seen from the side,and FIG. 5B shows the transport apparatus 42 as seen from the directionindicated by A in FIG. 5A.

In the state shown by FIGS. 5A and 5B, a block 27 is loaded into thetransport arm tip 60. This block 27 is obtained by the temporary fixingapparatus 41 temporarily fixing two wafers 11 being aligned by thestacking step executing section 45 and having surfaces contacting eachother, as shown in FIG. 3B.

The transport arm tip 60 includes a lower support plate 61, an uppersupport plate 62, and a support pillar 63 that supports the lowersupport plate 61 and the upper support plate 62. The upper support plate62 moves in a direction indicated by the arrows near the support pillar63 in FIG. 5A, i.e. an up and down direction when viewing the plane ofFIG. 5A.

The two wafers 11 to be layered are each held by the corresponding waferholder 21 using electrostatic adsorption, vacuum suction, or the like,and the two wafers 11 are aligned using the steps described above.

After the wafers 11 are aligned, the wafer holders 21 are temporarilyfixed by the temporary fixing apparatus 41 to form the block 27. Theblock 27 is fixed to the lower support plate 61 of the transport arm tip60 by electrostatic adsorption or vacuum suction.

After the block 27 is fixed to the lower support plate 61, the uppersupport plate 62 applies a pressing force from above while the block 27is being sandwiched. As a result, the block 27 is pressed into the stateshown in FIG. 3B, in which the block 27 can be transported from thestacking step executing section 45 to the pressure applying and heatingstep executing section 47. While the block 27 is sandwiched between thelower support plate 61 and the upper support plate 62, the block 27 maybe fixed to the upper support plate 62 by electrostatic adsorption orvacuum suction.

When the transport arm 43 (see FIG. 3B) transports the block 27, theblock 27 is accelerated when movement begins, during movement, and whenmovement stops. If the block 27 experiences a large amount ofacceleration, the possibility of misalignment occurring between the twowafers 11 in the temporarily-fixed block 27 becomes more likely, asdescribed further below in relation to FIG. 6. If misaligned wafers 11are bonded, the bonding is fixed without a connection being achievedbetween the electrodes of the wafers 11. Such a bonding decreases theyield of the 3-dimensional semiconductor apparatuses. To prevent this,the first embodiment detects misalignment based on the accelerationduring transport.

In the first embodiment, the acceleration sensor 64 for detecting theacceleration of the transport arm tip 60 during transport is providednear the support pillar 63 on the surface of the lower support plate 61onto which the block 27 is loaded. The acceleration sensor 64 detectsthe acceleration experienced by the block 27 during transport. Theacceleration detected by the acceleration sensor 64 is transmitted to acontrol apparatus, and the possibility of misalignment is judged by thecontrol apparatus based on the relation between acceleration andmisalignment amount measured previously, as shown in FIG. 6.

FIG. 6 is a graph showing the correlation between the accelerationimparted by the transport arm 43 of the transport apparatus 42 and theamount of misalignment occurring between the wafers, based onexperimentally measured results. As shown in FIG. 6, there is acorrelation between the acceleration experienced by the block 27 andmisalignment. Accordingly, the possibility of misalignment in the block27 can be detected by comparing the acceleration detected by theacceleration sensor 64 to a threshold value.

The possibility of misalignment can be detected by comparing thedetected acceleration to the threshold value of the accelerationdetected during transport, based on the relationship between theacceleration and misalignment measured in advance. If there is apossibility of misalignment, the pressure applying and heating step (S7)is not performed for the block 27. A possibly-misaligned block 27 istransported to a region other than the pressure applying and heatingstep executing section 47, and is examined with regard to whethermisalignment has occurred, for example.

If the examination indicates no misalignment, the block 27 istransported to the pressure applying and heating step executing section47 and the pressure applying and heating step (S7) is performed thereon.If the examination indicates misalignment, the stacking step isperformed again to prevent a drop in yield due to misalignment.Furthermore, the misaligned block 27 can be dismantled, and the stackingstep can then be performed again after some type of processing, such aspolishing of the wafers 11, has been performed.

In addition, the yield of the manufactured product is further improved.A block 27 that is not misaligned can undergo the pressure applying andheating step without being re-stacked, thereby increasing the throughputwhen manufacturing the layered 3-dimensional semiconductor apparatuses.In this way, a decrease in the yield due to wafer 11 misalignmentoccurring during transport from the stacking step executing section 45to the pressure applying and heating step executing section 47 can beprevented.

The acceleration during transport can be detected as long as theacceleration sensor 64 is provided on at least one of the two lowersupport plates 61. The acceleration sensor 64 can achieve the sameresult by being provided on components other than the lower supportplates 61, such as the support pillar 63 or the upper support plate 62.Furthermore, in addition to acceleration in an x-y direction parallel tothe plane of FIG. 3B, the acceleration sensor 64 may detect accelerationin the z-direction, which is perpendicular to the plane of FIG. 3B.

The misalignment possibility judgment (S6) can be performed any timeprior to initiation of the pressure applying and heating step (S7).Therefore, if the detection results are constantly monitored andacceleration that might cause misalignment is detected before the block27 reaches the pressure applying and heating step executing section 47,the transport of the block 27 to the pressure applying and heating stepexecuting section 47 can be stopped and the block 27 can be immediatelyexamined or transported to undergo the stacking step again.

First Modification

FIG. 7 shows a first modification of the present embodiment. Aside fromthe points described below, the first modification has the sameconfiguration as the first embodiment, and therefore redundantexplanation is omitted.

In the first modification, the acceleration sensor 64 is provided on anouter periphery of at least one of the two wafer holders 21 forming theblock 27. FIG. 7 shows an example in which both of the wafer holders 21are provided with the acceleration sensor 64.

The present modification, in the same manner as described above, detectsthe possibility of misalignment corresponding to detected accelerationbased on the relationship between acceleration and misalignment amountshown in FIG. 6, which is stored in the control apparatus. Therefore,the transport apparatus 42 of the present modification can prevent adrop in yield caused by misalignment during transport.

The acceleration sensor 64 used in the first embodiment and firstmodification may be a widely known acceleration sensor such as a deviceusing semiconductor distortion resistance elements. However, if theacceleration sensor 64 is provided to the wafer holders 21, theacceleration sensor 64 desirably has a high heat resistance since theacceleration sensor 64 is also heated during the pressure applying andheating step (S7). The relationship between acceleration andmisalignment amount shown in FIG. 6 may be stored in a memory of thecontrol apparatus as a conversion table or as an approximation function.

Second Embodiment

FIG. 8 shows the transport apparatus 42 that can detect misalignmentaccording to the second embodiment, as viewed from the side in a statewhere the block 27 is loaded in the transport apparatus 42 as shown inFIG. 3B. The transport apparatus 42 show in FIG. 8 has the sameconfiguration as the transport apparatus 42 according to the firstembodiment, and therefore redundant explanation is omitted.

In the second embodiment, there are two wafer holders 71 and 72, and areference surface 73 is formed on the wafer holder 71. The referencesurface 73 is provided with a gap sensor 75 for measuring a spacebetween the reference surface 73 and a reference surface 74 of the otherwafer holder 72. The gap sensor 75 is a sensor that detects a change ina gap according to a change in electrostatic capacitance, for example,and may be a widely known sensor such as an optical sensor usingtriangulation.

The second embodiment can use the gap sensor 75 to directly measure therelative misalignment between the two stacked wafers 11, and thereforehas a lower misalignment measurement error than the first embodiment.

If the misalignment detected by the gap sensor 75 is greater than orequal to a threshold value, the block 27 is returned to the stackingstep executing section 45 and is then transported to the pressureapplying and heating step executing section 47 after the realignment isperformed, thereby preventing a drop in the yield.

In the first embodiment, the first modification, and the secondembodiment, the misalignment between the two wafer holders 21 formingthe block 27 can be detected continuously during transport of the block27 from the stacking step executing section 45 to the pressure applyingand heating step executing section 47, and the block 27 can be returnedto the stacking step executing section 45 and realigned as soon as themisalignment amount exceeds the threshold value. Therefore, the timenecessary for realignment when misalignment occurs is shortened, therebyminimizing the drop in processing ability.

Third Embodiment

FIG. 9 shows the transport apparatus 42 that can detect misalignmentaccording to the third embodiment, as viewed from the side in a statewhere the block 27 is loaded in the transport apparatus 42 as shown inFIG. 3B. The transport apparatus 42 show in FIG. 9 has the sameconfiguration as the transport apparatus 42 according to the firstembodiment, and therefore redundant explanation is omitted.

In FIG. 9, the positional relationship between the wafers is obtained bymonitoring the reference marks 25 on the wafer holders 21 when twowafers 11 are stacked as described in FIG. 2C, and the relativepositions of the wafers 11 are adjusted. In the third embodiment, themisalignment between the two wafers 11 during transport is detected byusing a microscope 76 provided to the pressure applying and heating stepexecuting section 47 to monitor the positional relationship between thetwo reference marks 25 used for alignment after transportation from thestacking step executing section 45 to the pressure applying and heatingstep executing section 47. This method simply involves providing thepressure applying and heating step executing section 47 with themicroscope 76, and therefore has the benefit of lower cost.

Fourth Embodiment

FIG. 10 shows a schematic view of a control section 80 and the transportapparatus 42 according to the fourth embodiment. The configuration ofthe transport apparatus 42 is the same as the configuration of thetransport apparatus 42 of any of the other embodiments, and thereforeredundant explanation is omitted. As shown in FIG. 10, the transportapparatus 42 is provided with the control section 80 and a transport armdrive section 90.

The control section 80 includes a servo control section 82, anacceleration calculating section 84, a judging section 86, and a targetposition holding section 88. The transport arm drive section 90 includesan actuator 92 that causes each part of the transport arm 43 to operateand an encoder 94 that measures a movement amount of the actuator 92.The actuator 92 is driven by pressure of a working fluid or electricity.The encoder 94 may be formed using a linear encoder, a rotary encoder,or the like.

In the control section 80, the target position holding section 88 holdsinformation indicating a position to be reached by the transport arm 43.The servo control section 82 makes a comparison between a targetposition acquired from the target position holding section 88 and themovement amount of the actuator 92 received from the encoder 94, andsupplies the actuator 92 with drive power. In this way, the actuator 92can ensure that the transport arm 43 arrives at the target position.

In the control section 80, the acceleration calculating section 84 alsoreceives the movement amount of the actuator 92 from the encoder 94. Theacceleration calculating section 84 can calculate the accelerationcaused by the transport arm 43 by differentiating the informationindicating the movement amount, for example. The judging section 86 canjudge whether there is the possibility of misalignment between thewafers 11 in the block 27 transported by the transport arm 43 based onthe acceleration of the transport arm 43 received from the accelerationcalculating section 84.

If the judging section 86 detects that the acceleration exerted on theblock 27 by the transport arm 43 is greater than a prescribed thresholdvalue, the judging section 86 sets the target position in the targetposition holding section 88 to be a region other than the pressureapplying and heating step executing section 47. In this way, the block27 can be transported to a region where examination, re-processing,disposal, or the like can be performed.

The control section 80 described above can be further provided with theacceleration sensor 64 described in the first embodiment. In otherwords, the servo control section 82 can control the transport arm drivesection 90 to move the transport apparatus 42 within a range ofacceleration in which misalignment does not occur between the wafers 11of the block 27. It should be noted that the transport apparatus 42includes a plurality of movable joints and the like, and so theacceleration of the transport arm tip 60 does not necessarily match theacceleration predicted by the servo control section 82.

Therefore, even if the servo control section 82 performs the correctcontrol, the acceleration of the transport arm tip 60 might exceed theacceleration at which misalignment of the wafers 11 begins to occur. Tosolve this problem, the acceleration sensor 64 is provided to thetransport arm tip 60 to detect the actual acceleration of the transportarm tip 60.

In this case, even if the output of the acceleration calculating section84 is not above the threshold value, the judging section 86 judges thatthere is possible misalignment when the value detected by theacceleration sensor 64 is above the threshold value. Furthermore, evenwhen the output of the acceleration calculating section 84 is above thethreshold value, the judging section 86 judges that there is no possiblemisalignment when the value detected by the acceleration sensor 64 isnot above the threshold value, so that the pressure applying and heatingstep can be initiated. In this way, even if an abnormality, including anabnormality in the transport, is detected, the pair of wafer holders 21may still be transported to the pressure applying and heating stepexecuting section 47 if there is judged to be no possibility ofmisalignment. Therefore, the possibility of misalignment can be moreaccurately judged.

FIG. 11 is a side view of the transport apparatus 42 according to thefifth embodiment when the block 27 is loaded therein. Explanations ofportions of the fifth embodiment common to other embodiments areomitted. As shown in FIG. 11, the transport apparatus 42 includesreference marks 96 on the top surface of the lower support plate 61.Therefore, misalignment of the wafers 11 can be detected by detectingthe relative positions of the reference marks 96 on the lower supportplate 61 and the reference marks 25 of the wafer holders 21 loaded inthe transport arm tip 60.

Detecting the relative positions of the reference marks 25 and 96 can beperformed using a microscope 31, in the same manner as described in thethird embodiment for detecting the relative positions of the referencemarks 25 of the two wafer holders 21. In other words, the misalignmentof the block 27 caused by the transport can be detected by measuring therelative positions of the reference marks 25 and 96 both before thetransport apparatus 42 begins transporting the block 27 and after thetransportation. In this way, the possibility of misalignment between thewafers 11 of the block 27 can be known.

The reference marks 96 provided to the transport arm tip 60 are notlimited to mark patterns such as the alignment marks 23 of the wafers 11that can be detected by a microscope. Instead of the microscope 31detecting the reference marks 96, the reference marks 96 can be detectedby a magnetic sensor, an electric field sensor, am electrostaticcapacitance sensor, an interferometer, or the like using magnetism,electrodes, reflection, or the like. Furthermore, using an imagecapturing apparatus instead of the microscope 31 enables detection ofthe relative positions based on an image of the transport arm tip 60itself.

As described above, a judgment is made concerning the possibility ofmisalignment between two wafers 11 due to transport, and if the judgmentindicates the possibility of misalignment, an operator is informed ofthis fact and the alignment is checked, for example, prior to theprocess performed by the pressure applying and heating step executingsection 47, thereby preventing a drop in the yield of layered3-dimensional semiconductor apparatuses due to misalignment.Furthermore, since blocks 27 having no possibility of misalignment cancontinue to be processed, the throughput of the semiconductor apparatusmanufacturing apparatus is improved.

Therefore, by detecting the misalignment between wafers caused bytransport, the drop in yield due to bonding defects between wafers in amanufactured semiconductor apparatus can be prevented. The abovedescription involves stacking semiconductor apparatuses, but it isobvious that the same method and apparatus can be used to bondsubstrates other than semiconductor apparatuses.

While the embodiments of the present invention have been described, thetechnical scope of the invention is not limited to the above describedembodiments. It is apparent to persons skilled in the art that variousalterations and improvements can be added to the above-describedembodiments. It is also apparent from the scope of the claims that theembodiments added with such alterations or improvements can be includedin the technical scope of the invention.

1-26. (canceled)
 27. A method comprising: detecting a possibility ofmisalignment between a plurality of layered substrates during atransporting period.
 28. The method of claim 27, wherein the detectingduring the transport period includes detecting during a period from whenthe plurality of layered substrates have completed alignment by analigning section until an operation of one of applying pressure to andheating the plurality of layered substrates.
 29. The method of claim 27,further comprising judging whether a misalignment between the pluralityof layered substrates has occurred based on the possibility ofmisalignment.
 30. The method of claim 29, further comprising:transporting the plurality of layered substrates to a region other thana pressure applying section when the misalignment has occurred; andtransporting the plurality of layered substrates to the pressureapplying section when the misalignment has not occurred.
 31. The methodof claim 29, wherein the judging is based on a relative position betweenat least two of the plurality of layered substrates, a first substrateholder that holds the plurality of layered substrates, a secondsubstrate holder that holds the plurality of layered substrates, and atransporting section that transports the plurality of layeredsubstrates.
 32. The method of claim 29, wherein the judgment is based onwhether the possibility of misalignment is greater than or equal to athreshold value.
 33. The method of claim 32, wherein the judging isbased on an acceleration of at least one of the plurality of layeredsubstrates, a substrate holder that holds the plurality of layeredsubstrates, and a transporting section that transports the plurality oflayered substrates.
 34. An apparatus comprising: a control sectionoperable to detect a possibility of misalignment between a plurality oflayered substrates during a transporting period.
 35. The apparatus ofclaim 34, wherein the transport period includes a period from when theplurality of layered substrates have completed alignment by an aligningsection until an operation of one of applying pressure to and heatingthe plurality of layered substrates.
 36. The apparatus of claim 34,wherein the control section is further operable to judge whether amisalignment between the plurality of layered substrates has occurredbased on the possibility of misalignment.
 37. The apparatus of claim 36,further comprising a transporting section operable to transport theplurality of layered substrates to a region other than a pressureapplying section when the misalignment has occurred, and transport thesubstrate holder to the pressure applying section when the misalignmenthas not occurred.
 38. The apparatus of claim 36, wherein the controlsection is further operable to judge based on a relative positionbetween at least two of the plurality of layered substrates, a firstsubstrate holder which holds the plurality of layered substrates, asecond substrate holder which holds the plurality of layered substrates,and a transporting section which transports the plurality of layeredsubstrates.
 39. The apparatus of claim 38, further comprising a gapsensor mounted on at least one of the first substrate holder, the secondsubstrate holder, and the transporting section, the gap sensor operableto detect the relative position.
 40. The apparatus or claim 36, whereinthe control section is further operable to judge based on whether thepossibility of misalignment is greater than or equal to a thresholdvalue.
 41. The apparatus of claim 40, further comprising: a servocontrol section in communication with the control section, the servocontrol section including an encoder operable to detect an accelerationof at least one of the plurality of layered substrates and a substrateholder which holds the plurality of substrates, wherein the controlsection is further operable to judge based on the acceleration.
 42. Theapparatus of claim 40, further comprising: an acceleration sensormounted on at least one of a substrate holder which holds the pluralityof substrates and a transporting section which transports the pluralityof layered substrates, the acceleration sensor operable to detect anacceleration, wherein the control section is further operable to judgebased on the acceleration.
 43. A non-transitory computer-readable mediumhaving instructions stored thereon which, when executed by at least oneprocessor, cause the at least one processor to perform operationscomprising: detecting a possibility of misalignment between a pluralityof layered substrates during a transporting period.
 44. Thecomputer-readable medium of claim 43, wherein the operation of detectingduring the transport period includes detecting during a period from whenthe plurality of layered substrates have completed alignment by analigning section until an operation of one of applying pressure to andheating the plurality of layered substrates.
 45. The computer-readablemedium of claim 43, further comprising an instruction that, whenexecuted by the at least one processor, causes the at least oneprocessor to perform a further operation of judging whether amisalignment between the plurality of layered substrates has occurredbased on the possibility of misalignment.
 46. The computer-readablemedium of claim 45, further comprising instructions that, when executedby the at least one processor, cause the at least one processor toperform further operations of: transporting the plurality of layeredsubstrates to a region other than a pressure applying section when themisalignment has occurred; and transporting the plurality of layeredsubstrates to the pressure applying section when the misalignment hasnot occurred.